This invention relates generally to roadway barriers and in particular to movable roadway barriers used for traffic lane control.
The roadway barriers of the prior art were provided with a number of different devices for making them movable.
In one case, a plurality of overhead trusses spanning the highway and spaced apart along its length were used from which the barrier was suspended on cables. A trolley on each of the trusses moved the suspended barrier from one lane to another to facilitate a change of lane.
Other movable barriers utilized a plurality of spaced apart, laterally disposed slots in the roadway to house an hydraulic apparatus to move the barrier laterally from one lane to the next.
Another barrier utilized a complex system of vertically disposed, abutting pillars imbedded in a slot along the length of the roadway at the lane marker position. One lane utilized short pillars whose top surface was flush with the top of the roadway pavement. The other lane utilized taller pillars mounted in a similar slot in the adjacent lane. To change the barrier from one lane to the next, an apparatus pulled by a truck was used which similtaneously lifted the short pillars out of one lane and the tall pillars out of the adjacent lane and serially interchanged the two sets of pillars in the two slots.
All of these barriers and the apparatus to move them were somewhat complex and expensive. In addition, their method of installation involved some extensive revisions to the roadway adding considerably to the installation cost of the barrier and requiring expensive repair to the roadway when the barrier was permanently removed.